一个“裸露”的孤独黑洞，正在改写宇宙的历史
内容总结：
【宇宙观测新突破：韦伯望远镜发现早期宇宙“裸体”超大黑洞】
天文学家通过詹姆斯·韦伯空间望远镜（JWST）在宇宙早期发现了一个前所未有的超大质量黑洞QSO1。该黑洞质量相当于5000万个太阳，却几乎孤立存在，周围缺乏恒星环绕，被称为“裸体”黑洞。这一发现挑战了现有星系形成理论，或将改写宇宙早期演化史。
传统理论认为，黑洞形成于星系演化后期，由恒星坍缩后合并增长而成。但QSO1出现于宇宙诞生仅7.5亿年时（当前宇宙年龄约140亿年），且缺乏宿主星系迹象，表明黑洞可能先于星系形成。研究团队通过光谱分析证实，其周围气体几乎为纯氢（源于宇宙大爆炸），缺乏恒星核合成产生的重元素，进一步支持了这一猜想。
目前最受关注的假说源自霍金1971年的理论：宇宙大爆炸时的原始密度波动可能直接坍缩形成“原初黑洞”。另一种观点认为，早期气体云因辐射无法冷却碎裂成恒星，最终整体坍缩成黑洞。亦有理论提出，黑洞可能通过吞噬周围物质急速增长，而早期恒星快速消亡后留下孤立黑洞。
QSO1并非孤例。韦伯望远镜已发现300多个类似“小红点”天体，其性质引发激烈争论。尽管部分学者认为它们可能是特殊星系，但新研究通过直接测量气体运动速度，确证了QSO1的黑洞属性及惊人质量。
此次发现凸显了早期宇宙的混沌性与多样性。正如学者所言，人类此前对宇宙童年的认知“近乎一无所知”。韦伯望远镜正逐步揭示黑洞与星系形成的新路径，推动宇宙学理论体系重构。后续研究将聚焦这类天体的形成机制，以及它们如何演化为现今星系中心的超大质量黑洞。
中文翻译：
一颗“裸露”黑洞改写宇宙历史
引言
科学家在早期宇宙中发现了一个前所未有的黑洞。它体积巨大，且几乎孤立存在——周围几乎没有恒星环绕。这个可能代表全新类型的“裸露”巨型黑洞，彻底颠覆了教科书对早期宇宙的认知。
“这完全超出了认知尺度，”剑桥大学天体物理学家罗伯托·迈奥里诺表示。他在8月29日发布的预印本论文中揭示了该天体的特性：“这令人极度兴奋，且信息量极其丰富。”
科尔比学院天文学家戴尔·科切夫斯基评价道：“它突破了我们对宇宙可能性的想象边界。”
天文学家通过詹姆斯·韦伯太空望远镜（JWST）发现了这个裸露的黑洞。这个由NASA与合作机构建造的超级仪器，其重要使命之一就是揭示宇宙最初十亿年间星系的形成机制。这个被命名为QSO1、质量相当于五千万个太阳的新黑洞，与传统星系形成理论完全相悖——该理论认为黑洞并非星系起源的起点，而是恒星在引力坍缩后通过合并吞噬逐渐形成的。但迈奥里诺团队描述的却是一个没有母星系陪伴的孤独巨兽。
核心问题在于：这个黑洞如何形成？
最令人兴奋且最具争议的可能性，可追溯至英国物理学家斯蒂芬·霍金1971年提出的假说：黑洞诞生于宇宙大爆炸的原始混沌之中。若该理论成立，这个天体自宇宙诞生之初就存在于黑暗中，静待恒星与星系将其照亮。
QSO1是JWST运行初期发现的数百个类似“小红点”天体之一。天体物理学家尚不能确定这些红点是否全是黑洞，他们对宇宙混沌初开时期的认知仍充满困惑。但望远镜传回的图像显示，早期宇宙可能同时以协同或独立的方式制造巨大黑洞与星系，甚至可能存在黑洞优先于星系形成的场景——就像宇宙茶汤中悬浮的黑暗珍珠。
爱尔兰梅努斯大学理论学家约翰·里根坦言：“这些小红点告诉我们，我们的认知还远远不够。这个发现让整个领域为之振奋。”
淡红斑点
以色列本·古里安大学天文学家卢卡斯·富塔克在2023年首次看到JWST图像中三个隐藏在白色星系群中的红色光点时，就意识到QSO1的非同寻常。“它们立刻吸引了我的注意，”富塔克通过视频会议指着几乎难以察觉的红色斑点说道，“这三个红色点源分别位于这里、这里和上方。”
图像中星系与暗物质的巧合排列形成了天然“引力透镜”，如同玻璃透镜般弯曲了背景天体的光线，使望远镜能观测到更早期的宇宙。透镜效应将后方天体放大拉伸，有时会形成多重影像。正当富塔克测绘被透镜投射成香蕉状的多重星系影像时，他注意到了QSO1的三个红点。
这些红点之所以引人注目，是因为它们完全没有被拉伸的迹象。富塔克意识到，只有本身极其微小的圆点才能在引力透镜作用下保持点状外观。他推断这绝非星系，而必然是一个黑洞——一个质量极度密集、引力形成不可逃脱区域的天体。
随后六个月，富塔克团队指挥JWST对每个红点进行了40小时的光谱分析。研究证实QSO1极可能是一个发光黑洞，在不超过100光年的范围内聚集了数千万太阳质量，其影像展现的是宇宙仅7.5亿岁时的模样（当前宇宙年龄约140亿年）。
作为最早发现的小红点之一，QSO1引发了持续两年的学术争论。目前已知的300多个类似天体既具有发光黑洞的典型特征，又存在矛盾之处。尽管质量估算此前一直间接进行，但8月有研究团队分析百余个小红点后宣称，这些天体可能只是外形奇特的普通星系。
科切夫斯基表示：“整个领域都为之着迷。难得遇到完全无法解释的现象。”
深度观测
2024年12月，迈奥里诺与马克斯·普朗克地外物理研究所的汉娜·尤伯勒团队对QSO1进行了额外10小时观测。他们将影像放大至像素级别，测量每个像素的特定颜色，通过计算物质移动速度发现炽热气体正以狂暴涡旋状态运动——这印证了富塔克的初步发现。
五月和八月发布的两篇预印本论文详细揭示了QSO1的本质：其一，通过重构涡旋直接测得其环绕天体质量相当于五千万个太阳，与富塔克团队的发现吻合（这项直接测量法解决了长期争议）；其二，QSO1周围未见恒星星系，气体绕中心像素运行的模式表明质量集中于奇点；其三，黑洞至少占QSO1总质量的三分之二，其余为气体和零星恒星。里根认为实际比例可能高达90%，“这是前所未有的发现”。
最终，像素级光谱分析显示绕黑洞气体几乎全是氢元素——这种源于大爆炸的元素本应被恒星核聚变改造。QSO1似乎在许多邻近恒星生死轮回之前就已形成当前结构。
巴黎天体物理研究所理论学家玛尔塔·沃隆泰里指出：“最合理的解释是黑洞先于星系形成。”
起源之谜
天体物理学家当前的首要任务是厘清QSO1这类天体的形成机制，以及它们如何演化为现今星系中心的超大质量黑洞。早在宇宙十亿岁时就已存在的超大质量黑洞（可达数十亿太阳质量），始终是困扰学界的难题。
传统理论认为恒星坍缩合并形成黑洞需要漫长时间，难以解释宇宙十亿年时就存在的超大质量黑洞。QSO1的发现证明必然存在其他形成途径。
关于宇宙如何直接制造巨型黑洞，迈奥里诺团队倾向于霍金假说：大爆炸产生密度波动，极高密度区可能直接坍缩成黑洞，通过吸积物质持续成长。经过数亿年，这些“原初黑洞”可能发展为QSO1般的巨兽。
沃隆泰里表示：“这是目前最合理的解释，但我确信未来半年会出现无数新理论。”事实上耶鲁大学理论天体物理学家普里亚姆瓦达·纳塔拉詹团队早已提出两种非原初黑洞理论：其一是大爆炸产生的致密气体云因残余辐射无法冷却形成恒星，最终直接坍缩为黑洞；其二是特殊星区中某颗恒星坍缩成黑洞后像吃豆人般吞噬物质急速膨胀，其他恒星快速消亡后留下孤立黑洞。
尽管这些假说均可能成立，但唯一被排除的是教科书式的恒星坍缩-合并-吸积模型。
QSO1并非JWST发现的唯一非常规黑洞。另一个位于UHZ1星系（形成于大爆炸后五亿年内）的黑洞，通过JWST与钱德拉X射线天文台的联合观测，被确认为质量远超周边星系的奇特天体。该黑洞可能由气体云跳过恒星阶段直接坍缩形成——这套理论或许也适用于QSO1。
天文学家面临的挑战与兴奋在于，他们首次直面宇宙历史的新纪元，而解读这些景象异常艰难。里根生动比喻：此前通过观测“青少年期”星系推演宇宙理论，如今发现“学步期”的小红点则如同面对满地疯跑的幼童，迫使研究者以全新视角重构认知。
（编者注：普里亚姆瓦达·纳塔拉詹系《量子杂志》科学顾问委员会委员，本次仅接受访谈未参与稿件制作）
英文来源：
A Single, ‘Naked’ Black Hole Rewrites the History of the Universe
Introduction
A black hole unlike any seen before has been spotted in the early universe. It’s huge and appears to be essentially on its own, with few stars circling it. The object, which may represent a whole new class of enormous “naked” black holes, upends the textbook understanding of the young universe.
“This is completely off the scale,” said Roberto Maiolino, an astrophysicist at the University of Cambridge who helped reveal the nature of the object in a preprint posted on August 29. “It’s terribly exciting. It’s highly informative.”
“It’s pushing the boundaries on what we think might be true, what we think might happen,” said Dale Kocevski, an astronomer at Colby College who was not involved in the new research.
Astronomers spied the bare black hole using the James Webb Space Telescope (JWST) — a mega-instrument built by NASA and its partners in part to reveal how galaxies formed during the universe’s first billion years. This new black hole, which is as heavy as 50 million suns and is dubbed QSO1, clashes with the old, provisional account of the galaxy formation process, which did not start with black holes. Black holes were thought to have come along only after a galaxy’s stars gravitationally collapsed into black holes that then merged and grew. But Maiolino and his colleagues described a solitary leviathan with no parent galaxy in sight.
The question now is how this black hole came to exist.
The most exciting — and controversial — possibility dates back to a 1971 proposal from the British physicist Stephen Hawking: that black holes arose in the primordial soup of the Big Bang itself. In that case, the object would have been sitting in the dark since the universe’s first moments, waiting for stars and galaxies to illuminate it.
QSO1 is one of hundreds of similar-looking objects nicknamed “little red dots” that JWST has spotted in its first few years of peering into the deepest recesses of time. Astrophysicists can’t say yet whether these dots are all black holes or not, and in general they’re still confused about the universe’s chaotic childhood. But the telescope’s snapshots suggest a rowdy young cosmos that fabricated big black holes and galaxies both together and independently, or maybe even a universe where black holes were among the first large structures in existence — dark tapioca bubbles in an otherwise smoothly blended cosmic tea.
QSO1 and the rest of the little red dots “tell us we don’t know anything,” said John Regan, a theorist at Maynooth University in Ireland. “It has been really exciting and very electrifying for the field.”
Pale Red Dots
Lukas Furtak, an astronomer at Ben-Gurion University in Israel, knew QSO1 was extraordinary the moment he saw it — or the moment he saw its three reflections hiding among a smattering of splotchy white galaxies in an image taken by JWST in 2023. It’s “something that pops out immediately,” Furtak said over Zoom, clicking on three nearly imperceptible red specks. “There are three red point sources here, here, this one up here.”
In the image, a fortuitous placement of galaxies and dark matter has bent light rays traveling from background objects just as a glass lens might; this “gravitational lens” reveals objects deeper in the early universe than the telescope could otherwise see. The lens magnifies and stretches the stuff behind it, sometimes creating multiple images of it. Furtak was mapping out the banana-shaped smears of galaxies that the lens had projected into multiple places when he spotted the three red dots of QSO1.
The dots caught his eye because they show no signs of stretching. He knew that the only thing that looks like a small, round point even after getting stretched out is an even smaller, rounder point. This was no galaxy, he figured; it must be a black hole, a concentration of mass so dense that its gravity creates an inescapable zone of space around it.
Over the next six months, Furtak and collaborators directed JWST to stare at each of the three red dots for 40 hours each to take a census of the colors of light coming from the object, known as a spectrum. That study concluded that QSO1 is very likely a glowing black hole packing a mass of tens of millions of suns into a span of at most 100 light-years across, seen as it appeared when the universe was just 750 million years old. (Today the cosmos is approaching 14 billion years old.)
QSO1 was one of the first little red dots found. There are now over 300 of them, and a spirited debate over their nature has raged for two years. They have some classic features of glowing black holes, but not others. And estimates of their masses have (until now) been somewhat indirect. As a result, some astrophysicists have argued — as one group did in an analysis of more than 100 little red dots in August — that the objects are really just odd-looking galaxies with no black holes after all.
“The field has been obsessed with them,” Kocevski said. “Very rarely do you find things you can’t explain.”
Zooming In
In December 2024, Maiolino, together with Hannah Übler, now at the Max Planck Institute for Extraterrestrial Physics, and other collaborators, trained JWST on QSO1 for another 10 hours. They zoomed in on the dot until it resolved into a pixelated splotch, and measured the specific colors coming from each pixel. From these spectra, they calculated the speed at which the stuff shining in each pixel was moving toward us or away from us. The scientists found that bright material — likely hot gas — swirled around in a furious vortex, one that backed up Furtak’s preliminary findings.
Their closer look, detailed in a pair of preprints posted in May and August, definitively revealed QSO1’s identity.
One clue was its mass. By reconstructing the vortex, the team directly measured the mass of the object it was orbiting: 50 million times more massive than our sun. This matched what Furtak and his collaborators had found. (This result alone marks a big step forward: It suggests that the simpler indirect mass measurement based on the whole object’s spectrum works for young black holes, which had been a point of contention.)
Moreover, the group found no evidence of a starry galaxy around QSO1. The gas orbits the central pixel just as the Earth orbits the sun — indicating that mass is packed into a point. The team estimates that the black hole makes up at least two-thirds of the mass of QSO1, with the remaining third being gas and perhaps a smattering of stars. Regan, who wasn’t involved in the research, thinks they’re being conservative and that QSO1 could be as much as 90% black hole. “We’ve never seen anything like that before,” he said.
Finally, the pixel-by-pixel spectra also revealed that the gas orbiting the black hole is essentially pure hydrogen, an element that dates back to the Big Bang. Stars shine by fusing hydrogen into heavier atoms, and when stars explode, they scatter those heavier elements everywhere. QSO1 seemingly reached its current form before many nearby stars had lived and died.
“The most plausible explanation seems to be [that] the black hole developed before the galaxy,” said Marta Volonteri, a theorist at the Paris Institute of Astrophysics who helped with the new analysis of QSO1.
Shrouded Origins
A top task for astrophysicists now will be to sort out how QSO1 and its ilk formed, and how they became the supermassive black holes that sit at the centers of starry galaxies today. Supermassive black holes, which can weigh as much as billions of solar masses, can be seen anchoring galaxies by the end of the universe’s first billion years.
Supermassive black holes have long troubled astrophysicists. They know that galaxies can make black holes when their big stars burn and die. Those stellar corpses merge and feed on gas and dust, growing larger. The conventional story is that this growth eventually results in one giant black hole sitting in the center of the galaxy. The problem is that all this feeding and merging takes time, and astrophysicists struggle to imagine it happening fast enough to result in the supermassive black holes seen by the universe’s billion-year mark. So theorists have spent decades coming up with a menu of alternative theories about their formation.
Now QSO1, which has no galaxy to speak of, shows that there must indeed be another way.
So how might the universe directly manufacture gigantic black holes? Maiolino’s group favors Hawking’s proposal. The Big Bang produced an infant universe that was denser in some spots than in others. A sufficient density could have collapsed straight into a black hole, which would then have grown by absorbing any matter around it. After hundreds of millions of years, some of these “primordial” black holes might have reached gigantic proportions — appearing much like QSO1.
“It’s the most plausible explanation that I see,” Volonteri said. But “I’m sure in the next six months there will be a thousand people coming out with other theories.”
They won’t have to wait six months. Even before QSO1’s discovery, Priyamvada Natarajan, a theoretical astrophysicist at Yale University, and collaborators had already published two non-primordial theories that could account for QSO1’s origin.
The first theory supposes that the Big Bang produced dense spots that didn’t collapse immediately. Instead, they evolved into clouds of gas over hundreds of thousands of years. Residual radiation from the Big Bang stopped these clouds from cooling and fracturing into stars, letting them become massive enough to collapse straight into black holes. In a paper posted in June, researchers led by Wenzer Qin at New York University called these slightly later-blooming giants “not-quite-primordial” black holes.
Or perhaps QSO1 did come from a galaxy after all — one that quickly formed, made a big black hole, and vanished. In 2014, Natarajan and Tal Alexander of the Weizmann Institute of Science in Israel described a scenario where one star in an especially starry region collapses into a large black hole that then zooms around like Pac-Man, hoovering up gas and ballooning to a huge size. The other early stars then wink out quickly, leaving the giant black hole to its own devices.
None of these origin stories fits QSO1 snugly, though each is possible. The only scenario that’s essentially ruled out is the textbook one of stars collapsing, merging and feeding on an orbiting disk of gas.
QSO1 isn’t the first unconventional black hole spotted by JWST, though it’s the barest one. Another striking find sits in a galaxy called UHZ1, which formed less than half a billion years after the Big Bang. By combining JWST observations with X-rays collected from the object by the Chandra X-ray Observatory in 2022, Natarajan and collaborators determined that UHZ1 is also more black hole than surrounding galaxy. This and a handful of other features led the group to conclude that UHZ1’s black hole was born when a cloud of gas largely skipped the star stage and collapsed directly — a theory that also might work for QSO1.
The challenge — and excitement — for astronomers is that they’re confronting a new era of cosmic history for the first time, and it’s proving tough to make sense of the scene. Regan compares the situation to developing a whole theory of humanity based on adults and teenagers — the adolescent and mature galaxies we could see prior to the launch of JWST. Now observing little red dots is the equivalent of discovering toddlers, messy new entities that are hard for researchers to interpret based on what they’ve seen before. “It’s a different vibe,” he said. “They’re running around like lunatics.”
Editor’s note: Priyamvada Natarajan is a member of Quanta Magazine’s scientific advisory board. She was interviewed for this story but did not otherwise contribute to its production.